The regulation mechanism and deposition behavior of sprayed particles in vertical groove were studied by means of groove constrained electro-explosive spraying. The results show that when the constraint depth reaches 20 mm, i.e. the spraying distance is 100 times of the wire diameter, the continuous and uniform coatings can still be obtained. With the constraint width decrease from 6mm to 2mm, the morphology of coating surface changed from "Hill-like" to "pancake-like"，and the coating thickness increases significantly; Increasing energy density from 57J/mm3 to 152J/mm3 can also improve coating thickness and uniformity. By analysis the collected spraying particles, it was found that reducing the constraint width and increasing the energy density can effectively refine the spraying particles and make the particle size distribution more uniform. It is concluded that the "thermal expansion effect" caused by Joule heating and the "pressure effect" associated with breakdown arc can work together to regulate the sprayed particles with the change of energy density and constraint parameters, which will resulting in different deposition behavior.