The invention provides a method for combination exploitation of planar adjacent small fault blocks by cross-fault-block horizontal well. The method includes: through accurate geological research and structural interpretation, clearly determining geologic features and structural features of a research area; determining level difference of target horizons on two sides of a fault; computing controlled reserves and increasing recoverable reserves, and combining small fault block remaining oil enriched areas adjacent on a plane; optimally designing plane positions, vertical distance to the top and horizontal section length of multiple targets of the cross-fault-block horizontal well; performing on-site trajectory tracking regulation, judging drilling conditions, clearly determining the geologic position of a drill bit, and ensuring that the horizontal well successively drills and encounters an objective oil reservoir. By the aid of the method for combination exploitation of the planar adjacent small fault blocks by the cross-fault-block horizontal well, the problem of poor economic benefit of drilling in single planar remaining oil enriched areas of the complicated small fault blocks is solved, and the purpose of benefit exploitation of the complicated small fault blocks is achieved.