A stepwise slot allocation method and apparatus applicable to a node in a wireless network and includes: by the node, determining an initial boundary value of a slot for slot allocation at a current slot allocation stage; calculating a slot length needed by the node at the current slot allocation stage; and selecting a slot index needed by the current slot allocation stage starting from the initial boundary value. By using the method, the slot allocation is combined with an amount of traffic in the network, and slot index of each node is more proper. And it is ensured that one packet corresponds to a slot, and a case will not occur where a slot is reserved but not used.