The UART pins are the pin 0 for Rx and the pin 1 for Tx. I'm confused because you said that you connected pin 2 to pin 4. Are those the pins you connected? If so, please use the pins 0 and 1 instead. The pins 2 and 4 are not for UART purposes.
First, I connected pin0 (0Rx) to pin1(1TX), but nothing read;
Then I see the hw guide that said the pin2 and pin4 is for flow control, and Uart1 with flow control, so i also connect pin2 to pin4, but it doesn't work yet.
I am no idea of how to use Edison's uart
To be clear - you have Pin 0 connected to Pin 1 AND you have Pin 2 connected to Pin 4?
1. Can you turn off flow control?
2. You say "write is ok" - how are you verifying? Did you put a 'scope on it?
Have you tried with the MRAA example for the UART? You can check it here: mraa/uart.c at master · intel-iot-devkit/mraa · GitHub. It should configure the UART to send data.
Additionally, you could test the UART with an Arduino sketch. The SerialEvent code is a good example to test the UART; however you have to change the "Serial" object by "Serial1". This example can be found in the Arduino IDE under File>Examples>Communication>SerialEvent