The remainder particles in empty-sealed optocoupler will seriously affect its reliability. Particle impact noise detection (PIND) is the main method for detecting the remainder particles, but it presents an undetected error rate. Based on the voltage sampling data in PIND test, the detection probability model is established in this paper. The effects of distribution region and test frequency on the detection probability of typical kinds of particles with the same mass were studied by using the model. The results show that the detection probability of ceramic particles and conducting resin particles are greatly affected by hardness of impact object and particle adhesion, which makes the detection probability in different regions present obvious differences, and the overall detection probability of the latter is small due to the weak elasticity of particles, but will obviously improve after the test frequency rises. The results also show that the detection probability of short gold wire is large and stable due to its weak adhesion and strong elasticity. Based on this, the control and detection method for typical remainder particles is proposed, which will effectively improve the reliability level of the optocoupler. The model and research method in this paper can be extended to similar research on other empty sealed components.