Read INPUT state of Ultrasonic Sensor SR-05

Here's the code of reading INPUT state of Ultrasonic Sensor

const int trigPin = 13;
const int echoPin = 7;

//Set up
void setup(){
  Serial.begin(9600);  // Initialize serial communication.

  // Set pin mode for SR-05
  pinMode(echoPin, INPUT);
}

void loop () {
  digitalWrite(echoPin, HIGH);
  Serial.println(digitalRead(echoPin));
  delay(400);
}

The value print out is 0 (zero) which is wrong. Why is that?