In this paper, we consider subordinate symmetric Markov processes which correspond to non-killing Dirichlet forms enjoying heat kernel estimates on a metric measure space with the volume doubling property. We obtain estimates of the jump kernel of the subordinate process and establish equivalent conditions for the jump kernel following Liu-Murugan. In particular, we clarify the scale of the jump kernel, which is different from the diffusion type. This result is appliable to non-subordinate processes by the transferring method, which uses stability of Dirichlet forms.