The invention relates to the technical field of electric control locks, in particular to an electric control lock with a build-in power source and a control method of the electric control lock and aims to solve the technical problem that according to a box body provided with the electric control lock, a power supply device for supplying power to the electric control lock and power lines disturb signal lines in the box body. To achieve the purpose, the electric control lock with the build-in power source comprise a lock shell, the lock shell is internally provided with an extensible and retractable lock tongue penetrating through the lock shell, the lock tongue can be driven by an automatic drive device located in the lock shell, the electric control lock further comprises a power supplyingdevice for supplying power to the automatic drive device, and the power supplying device comprises a solar cell panel arranged on the electric control lock. According to the electric control lock, due to the fact that the electric control lock is internally provided with the power supplying device, it does not need to install the power supply device or the power lines in the box body, in this way, the phenomenon that the electric control lock disturbs signals of the signal lines in the box body is reduced, furthermore, the frequency of changing and maintaining the power supplying device can be reduced through solar cells, and the working reliability of the electric control lock is improved.