The invention discloses a preparation method for a transition bimetallic chalcogenide electrocatalyst, belonging to the technical field of synthesis of electrocatalytic materials. According to the invention, sulfide precursors are obtained by hydrothermal reaction of different transition metal salts and different sulfur sources in different proportions, and selenium powder is doped through a low-temperature sintering method, so transition metal chalcogenide catalysts with excellent electrocatalytic performance are obtained. The preparation method comprises the following concrete preparation steps: (1) successively subjecting a carbon cloth (3 * 3 cm<-2>) to ultrasonic treatment in acetone, ethanol and water for 10 minutes for subsequent usage; (2) mixing a transition metal salt and a sulfur source into water in proportion, and carrying out uniform mixing under stirring; (3) transferring a uniformly-mixed solution to a reaction kettle, placing the ultrasonically-treated carbon cloth into the reaction kettle, maintaining a temperature at 180 DEG C for 12 hours, then carrying out cooling to a room temperature, taking the carbon cloth out of the reaction kettle, then successively washing and cleaning the carbon cloth with ethanol and water, and carrying out drying; (4) mixing another transition metal salt and the sulfur source into water in proportion, carrying out uniform mixing under stirring; (5) transferring a uniformly-mixed solution to the reaction kettle, placing the carbon cloth obtained in the step (3) into the reaction kettle, maintaining a temperature at 180 DEG C for 12 hours, carrying out cooling to a room temperature, taking the carbon cloth out of the reaction kettle, successively washing and cleaning the carbon cloth with the ethanol and the water, and carrying out drying so as to obtain bimetallic sulfide; and (6) subjecting the carbon cloth obtained in the step (5) and the selenium powder to sintering in different proportions at different temperatures so as to obtain transition bimetallic chalcogenide nanometer materials. The catalyst material obtained by using the method provided by the invention shows good electrocatalytic performance, has simple preparation process and low cost, and is applicable to large-scale production.