In rice-frog symbiosis system, the anti-insect effect of frog can not only improve the rice quality but also increase the profit of frog raising. Most frog released in this system is usually small with single weight less than 100 g. Experiments were conducted to explore the influences of frog weight on anti-insect effect and raising profit. The results showed that released with single frog weight of 75 g can reach the profit level as that of the single frog weight of 100 g.