In order to solve the problem of finding the fixed plot difficulty for continuous forest inventory, improve the efficiency and reduce the cost, a permanent sample plot marking device was designed based on the principle of remote control alarm and GNSS positioning. The marking device was composed of main program module, positioning decoding module, remote control alarm module, the data transmission module, the sample update information storage module, etc. FreeRTOS operating system was transplanted on Cortex-M3, and C++ was used to carry out most of the functions such as remote control, low frequency positioning etc. For the location of information data transmission, a sample API was developed on the WeChat platform by calling a Baidu map to realize the route planning for general mobile phone users. When the investigators load the APP for searching the plot in a certain area of the marker, the remote alarm would automatically start ringing. Then the location would be sent to the handset, which would help them to find the marker more quickly. Verified by experiments, the efficiency of the marking device was about 324% higher than that of the traditional sample plot. Meanwhile, the device can directly read and write the historical information and real-time monitoring data. It was showed that the equipment can solve problems such as marking device finding difficulties and no history inventory information. Therefore, it can be used and promoted in the permanent plot for continuous forest inventory in the future.