A separable valve assembly comprises a valve mount 6 and a valve body 7, which can be readily put together in use and separated for replacement of either of the two. The valve mount 6 has a cavity with two inclined wall planes and an arcuate bottom surface in conformity with the shape of the valve body so that the valve body 7 can be tightly wedged therein and secured in place by a number of bolts 81 and nuts 8 with a sealing element 72 disposed between the contact surfaces for leakage-preventing purpose, and a valve body lifting bolt 61 is disposed at the bottom of the mount 6 for facilitating separation of the valve body 6 from the assembly.