The invention relates to an orifice jet velocity measuring experimental device suitable for a multi-field coupling condition. The orifice jet velocity measuring experimental apparatus comprises a bracket, a high-temperature circulating fan, a PIV system and an angle adjusting system. Upper and lower chambers are disposed on the bracket and are arranged oppositely. An observation area is formed between an upper air hole plate and a lower air hole plate. A feed inlet and a feed outlet are formed at the left and right sides of the observation area respectively. The PIV system is located on the front side of the observation area and includes a digital camera capable of performing position adjustment in XYZ directions and a dual-pulse laser. The experimental device of the invention is simple and used for simulating orifice jet velocity measurement under the multi-field coupling condition in a plurality of industrial fields, recycles tracer particles in the fluid, and has an adjustable shooting area, experimental parameter diversity and shooting position accuracy.