I am suspicious that my board is not compatible with the 328PB. I copied the circuit of Arduino Uno. I don't know whether that could be the problem??
Look very close at pins 3 and 6 of the 328p-AU and 328pb-AU package (U may or may not show on the part).
But the serial download still works with PD0(RX)PD1(TX) VCCIN and DTR. Basically, there's nothing different with code uploading circuit. The problem remains...
"Then, I have tried to upload my sketch to my project board like this but it responded nothing......".
But when I change the bootloader to 16Mhz external, it showed "avrdude: stk500_recv(): programmer is not responding" message again.