Disclosed an LED drive circuit, which is configured to switch the connection of a plurality of LED loads between parallel connection and series connection. When an input voltage is low, the LED loads are controlled to be in parallel connection, and the transistors provided on corresponding parallel branch circuits are controlled to operate in a linear state for regulating the current flowing through the parallel branch circuits. When the input voltage increases, the LED loads or LED drive modules are controlled to be in series connection, and the transistors provided on the series branch circuits are controlled to regulate the current flowing through all the LED loads. Accordingly, on one hand, all the LED loads have a same operating time, on the other hand, all the LED loads operate during most time of every operating cycle, which improves the lifetime of the circuit and the utilization of the LED loads.