The invention discloses a down-hole coal seam earthquake CT detection vibroseis and method based on seismal waves excited by a spring. The down-hole coal seam earthquake CT detection vibroseis is characterized by comprising a spring striking mechanism and a power mechanism, wherein the spring striking mechanism is installed inside a sleeve (11), the sleeve (11) is fixedly installed in a hole drilled in a roadway wall through a fixing mechanism, the spring striking mechanism comprises the spring (12), a hammerhead (15) and a base plate (16), one end of the base plate (16) is inserted into the sleeve (11), the other end of the base plate (16) is located outside the sleeve (11) and abuts against the bottom of the drilled hole, the spring (12) drives the hammerhead (15) to strike the base plate (16), and the end, outside the sleeve, of the base plate (16) strikes the bottom of the hole, so that the controllable seismal waves are generated in a coal seam; a guide groove is formed in the hammerhead (15), movement guiding is achieved through a guiding pin (14) installed on the sleeve (11), and the power mechanism is used for driving the hammerhead (15) to compress the spring (12), so that the hammerhead (15) is in the excited state. The down-hole coal seam earthquake CT detection vibroseis is simple in structure and easy to obtain.