In the short-term earthquake prediction method, the geomagnetic low-point displacement method and the rhythm of multiplied nine days after a magnetic storm are proposed by Chinese earthquake scientists. The two methods have been verified for decades, but it is still difficult to use them to accurately predict the earthquake. In view of this, our suggestion is to use the low-point displacement method as the main prediction scheme, and the rhythm of multiplied nine days after a magnetic storm as the second and supplementary prediction scheme. We combine the two methods together to predict the occurrence time of a strong earthquake. It is hoped that more data can be collected to improve the accuracy of the method in the field of short-term earthquake prediction.