Hydraulic brake circuit control system and telescopic boom forklift

The invention discloses a hydraulic brake circuit control system and a telescopic boom forklift, and the hydraulic brake circuit control system comprises a service brake circuit which comprises an axle brake, a service brake valve and a flow regulating valve, a working oil port in one side of the service brake valve is connected with an axle brake through a service brake working oil way so as to control the axle brake to charge or discharge liquid; the hydraulic pump is connected with an oil inlet in the other side of the service brake valve through a first pumping oil way, and the flow adjusting valve is arranged in the first pumping oil way to adjust the liquid filling flow or the liquid discharging flow of the axle brake. A traditional prefill valve and a prefill loop are omitted, the brake oil is directly supplied to the service brake loop through the hydraulic pump, the brake oil is supplied sufficiently, response is fast, and the whole brake system is further simplified. For axle brakes of different spe