In order to detect soil nitrate nitrogrn content rapidly with low cost, an automatic multi-channel detection platform for soil nitrate nitrogrn was developed. The self-designed PPy(NO-3) ion selective electrode (ISE) was used to sense the nitrate ion in solutions. The platform response time, effects of rinsing time on platform calibration and soil nitrate-nitrogen detection were discussed with a series of standard nitrate solutions, nitrate-nitrogen contents of which were ranging from 1~250 mg/L. Testing results showed that response time of the platform was 40 s when it was used in soil nitrate-nitrogrn detection. During system calibration and soil nitrate extracts determination, rinsing operation for the system could be carried out directly with the next sample solution. And rinsing 2 times could achieve a desirable effectiveness. No significant differences were got between the results detected separately by the platform and manual operation. Also, different channels of the platform possessed similar detection performances and good consistency. The system validation results conducted with 20 soils indicated that satisfied correlation was obtained between the soil nitrate-nitrogen results detected with the platform and ultraviolet spectrophotometric method. The determination coefficient (R2) was 0.91.