The regulation mechanism and deposition behavior of sprayed particles in vertical groove were studied by 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 decreasing from 6 mm to 2 mm, the morphology of coating surface changes from "hill-like" to "pancake-like", and the coating thickness increases significantly; increasing energy density from 57 J/mm3 to 152 J/mm3 can also improve coating thickness and uniformity. By analyzing the collected spraying particles, it is 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 result in different deposition behaviors. © 2020, Science Press. All right reserved