In order to conserve water and timely irrigation and avoiding midday irrigation plant, design of a solar panel to generate electricity to power the automatic irrigation system. Through the humidity sensors, temperature sensors collect the temperature and humidity of the soil，through photosensitive resistor collect light value.The collected signal is converted into a signal which can be recognized by a single chip computer.The signal is transmitted to MCU and is compared with the set value after data processing.Light intensity value, humidity value can be displayed in real time by LCD.The set valuecan be adjusted by Keys.If overrun, the buzzer will alarm.And While the valve will be opened for irrigation.Through the experimental debugging, the whole system structure is reasonable, the operation is good.the irrigation requirementscan be met.