plz check this program

char inchar; //Will hold the incoming character from the Serial Port.

int relay = 13;
int val;
int tempPin = 1;
int sensorPin = A0; // select the input pin for the potentiometer
int ledPin = 13; // select the pin for the LED
int sensorValue = 0; // variable to store the value coming from the sensor
#include <SoftwareSerial.h>

SoftwareSerial mySerial(9, 10);

void setup() {
// prepare the digital output pins
pinMode(relay, OUTPUT);
digitalWrite(relay, LOW);
//Initialize GSM module serial port for communication.

Serial.begin(9600);
delay(3000); // give time for GSM module to register on network etc.
Serial.println("AT+CMGF=1"); // set SMS mode to text
delay(200);
Serial.println("AT+CNMI=3,3,0,0"); // set module to send SMS data to serial out upon receipt
delay(200);

// declare the ledPin as an OUTPUT:
pinMode(ledPin, OUTPUT);
mySerial.begin(9600); // Setting the baud rate of GSM Module
Serial.begin(9600); // Setting the baud rate of Serial Monitor (Arduino)
delay(100);

}

void loop()
{
val = analogRead(tempPin);
float mv = ( val/1024.0)5000;
float cel = mv/10;
float farh = (cel
9)/5 + 32;

Serial.print("TEMPRATURE = ");
Serial.print(cel);
Serial.print("*C");
Serial.println();
delay(1000);

// read the value from the sensor:
sensorValue = analogRead(sensorPin*57.5);
// turn the ledPin on
digitalWrite(ledPin, HIGH);
// stop the program for milliseconds:
delay(sensorValue);
// turn the ledPin off:
digitalWrite(ledPin, LOW);
// stop the program for for milliseconds:
delay(sensorValue);
if(sensorValue>230)
Serial.write(mySerial.read());
SendMessage1;
if(cel>60);
Serial.write(mySerial.read());
SendMessage2;
//If #a1 comes as sms, relay should goes up.
if(Serial.available() >0)
{
inchar=Serial.read();
if (inchar=='#')
{
delay(10);
inchar=Serial.read();

//first led
if (inchar=='a')
{
delay(10);
inchar=Serial.read();

if (inchar=='0')
{
digitalWrite(relay, LOW);
}
else if (inchar=='1')
{
digitalWrite(relay, HIGH);
}
delay(10);

}
}
Serial.println("AT+CMGD=1,4"); // delete all SMS
}

}
void SendMessage1()
{
mySerial.println("AT+CMGF=1"); //Sets the GSM Module in Text Mode
delay(1000); // Delay of 1000 milli seconds or 1 second
mySerial.println("AT+CMGS="+91xxxxxxxxxx"\r"); // Replace x with mobile number
delay(1000);
mySerial.println("over voltage detected");// The SMS text you want to send
delay(100);
mySerial.println((char)26);// ASCII code of CTRL+Z
delay(1000);
}
void SendMessage2()
{
mySerial.println("AT+CMGF=1"); //Sets the GSM Module in Text Mode
delay(1000); // Delay of 1000 milli seconds or 1 second
mySerial.println("AT+CMGS="+919746978576"\r"); // Replace x with mobile number
delay(1000);
mySerial.println("over temperature detetected");// The SMS text you want to send
delay(100);
mySerial.println((char)26);// ASCII code of CTRL+Z
delay(1000);
}

Check it for what?

Too many delays, not enough F() macros, no code tags.

2/5

SoftwareSerial mySerial(9, 10);

Can you post a picture of a mySerial? Clearly, you do not have a mySerial connected to the Arduino. So, that name is meaningless. Meaningful names go a long ways towards making the code self-documenting and understandable.

What IS connected to the software serial pins? If it is the SMS device, what is this doing?

Serial.println("AT+CMGF=1"); // set SMS mode to text

That string will not get to the SMS device.