The embodiment of the invention provides an event subscription method and device based on a block chain, and relates to the technical field of science and technology finance. The method comprises: anintermediate server receiving a subscription request sent by a client side, determining all key event sequences corresponding to a target theme and roles corresponding to all the key event sequences according to the subscription request, and determining the key event sequences by counting historical business information of different roles; and determining a target event sequence from all the key event sequences corresponding to the target theme according to the role corresponding to the client, and sending the target event sequence to the client. The key event sequence is determined by counting the historical business information of different roles. Therefore, when the subscription request is received, the key event sequence corresponding to the client side can be determined according to the role of the client side and sent to the client side instead of sending the whole event sequence to the client side, so that information which is not concerned by some consumers is prevented from being returned, the bandwidth is saved, and the service speed can be ensured when the subscription is violently increased.