The embodiment of the invention provides a preparation method of a monolithic silicon-based photoelectric integrated chip. A laser device structure grows by etching a pattern window on an SOI substrate, a detector structure grows on a silicon waveguide layer in the SOI substrate, and a laser device and a detector are connected through the etched silicon waveguide structure, so that integration ofthe on-chip laser device, the detector and the silicon waveguide structure is achieved. According to the preparation method of the monolithic silicon-based photoelectric integrated chip, the laser device structure grows by directly etching the pattern window, high repeatability and reliability are achieved, large-scale preparation can be achieved, the cost is greatly reduced, good application prospects are achieved, the blank that a practical on-chip photoelectric integration cannot be achieved through a direct selective area epitaxy mode at present is made up for, and the method particularlysolves the on-chip integration problem of the laser device and other devices.