The invention discloses a method for optimizing tight oil horizontal well crack network parameters through the transformation volume, and belongs to the field of tight oil horizontal well reservoirs. According to the method, according to a tight reservoir, firstly, the geologic feature of the reservoir is evaluated, the specific reservoir condition for volume fracture to form a volume crack network system is explicated, then, the influences of different transformation volumes and crack arrangement modes of horizontal well volume fracture on capacity are studied, and the specific crack network parameters are optimized. The method at least includes the steps that firstly, a basic crack network feature comprehensive evaluation method for tight reservoir volume fracture is established; secondly, a capacity prediction and simulation model method for tight oil volume fracture is established. The tight oil layer horizontal well fracture crack network parameters are optimized through the transformation volume formed in the fracture process, the transformation volume is formed in a tight oil layer, a matrix seeps towards a crack at the shortest distance, the driving pressure of effective flow is greatly reduced, and flow under the extremely-low permeability condition is achieved; the single well capacity can be greatly improved.