A Source Meter has been designed, which is based on ARM Cortex-M4. The output of voltage and current source is implemented by the AD5422, and the output accuracy is 5 digits in the range of 0-10V and 0-20mA,the error is within 0.02%.. The measurement functions of voltage, current, and resistance are realized by LTC2440, and the measurement accuracy reaches six and a half digits,the voltage measurement error is less than 0.003%. The measurement of the signal is sampled by ADC, which is amplified by strobe, the sliding mean filter method has been used to filter the sampling disturbance, and the least square method is used to calibrate the data. The measurement and output data are displayed on the LCD. The digital source meter has low cost, high digital integration and easy operation, which is suitable for being widely used in the undergraduate teaching experiment of electronic information.