The utility model relates to a high -low pressure switching circuit of LLC transform output, including output, the vice limit of a n transformer and a n rectifier, wherein n is greater than 1, the interchange side of n rectifier is connected at the both ends on the vice limit of a n transformer, the high -pressure side of a low voltage terminal connecting m+1 rectifier direct current side of a m rectifier direct current side, wherein 0<, M<, N, be equipped with select switch between vice limit of transformer and output for through the size of selecting to insert the output voltage of the quantity regulation output of output rectifier. The utility model provides a technical scheme, the quantity of rectifier that can be through the select switch controlled access output is adjusted output output voltage size to the nonadjustable problem of LLC converter output voltage has been solved.