High and low dual-speed pressurizing system for rotary drilling rig

A high and low dual-speed pressurizing system for a rotary drilling rig includes a main hydraulic circuit (3) having larger output flow, an auxiliary hydraulic circuit (4) having less output flow and a pressurizing oil cylinder or pressurizing winch (5). The main hydraulic circuit (3) and the auxiliary hydraulic circuit (4) are connected in parallel and then connected to the pressurizing cylinder or pressurizing winch (5). A hydraulic pump may supply oil to the pressurizing cylinder or pressurizing winch (5) when the three-position four-way valve (3.2, 4.2) of the main hydraulic circuit (3) or the auxiliary hydraulic circuit (4) is controlled. The pressurizing cylinder or pressurizing winch (5) may be lifted quickly when the main hydraulic pump (3.1) supplies oil to it, and may be pressurized slowly when the auxiliary hydraulic pump (4.1) supplies oil to it.