In order to accurately monitor the sowing state of rice hill-direct-seeding machine in real time and improve stability, taking rebound dipper rice hill-direct-seeding metering device as research carrier, PVDF piezoelectric film as sensing element, ATmega328P MCU as control core, a monitoring system for rice hill-direct-seeding based on piezoelectric impact method was designed. Based on analysis of seed throwing trajectory of rice seeds, seed-conducting tube which could be used to assist monitoring and indenting seed-conducting was designed, and the installation position of PVDF piezoelectric film sensor was determined. The control algorithm to four kinds of seeding faults was determined with characteristics of multi-seed hill-direct-seeding. The whole hardware circuit of system was designed and Bluetooth wireless serial transparent transmission APP was developed, so that wireless communication between the host computer and the slave computer could be realized. The results of bench test showed that the sensitivity of system can reach more than 90.83% under different working conditions, so the system can realize the effective capture of signal. The field performance experiment results showed that acousto-optic alarm operation can be done when fault was happened. Counting reseeding hill amount and miss seeding hill amount were shown on Bluetooth wireless serial transparent transmission APP, which were contrast with actual reseeding hill amount and miss seeding hill amount counted by manpower, and the minimum mean values of reseeding monitoring accuracy, miss seeding monitoring rate and effective monitoring rate of system were 81.79%, 80.42% and 97.67%, respectively, which can meet the monitoring requirement of rice hill-direct-seeding and enhance the operation quality of rice hill-direct-seeding.