A fast steam turbine starting system based on automatic temperature control comprises a gas inlet pipeline, a fast starting device communicated with the gas inlet pipeline, a control cabinet connected with the fast starting device, a gas outlet pipeline connected with the control cabinet, a steam turbine medium-pressure cylinder, a steam turbine high-pressure cylinder, a gas guiding and water draining pipe tee joint, a gas guiding and water draining pipe connected with the gas guiding and water draining pipe tee joint, a gas guiding and discharging pipe tee joint, a gas guiding and discharging pipe connected with the gas guiding and discharging pipe tee joint, and a communicating pipe rear cylinder access door; the fast starting device is provided with gas collecting box temperature measuring points and gas collecting boxes; and the steam turbine high-pressure cylinder is provided with a high-pressure cylinder temperature measuring point. According to the fast steam turbine starting system based on automatic temperature control, before a steam turbine is started, clean and dry hot air is conveyed into a cylinder body through a pipeline, a cylinder, a flow passage, a high-pressure rotor and a medium-pressure rotor are pre-heated, and therefore the turbine warm-up time can be shortened after the steam turbine is started.