Disclosed are a data transmission method and apparatus, a search space optimization method and apparatus and a storage medium. The data transmission method includes that a UE sends a random access preamble to a base station and receives a random access response sent by the base station, the UE sends a first request message to the base station, and the UE in a first state receives an uplink grant sent by the base station and sends uplink data to the base station by using the uplink grant, where the first state includes an idle state or an inactive state. The UE can transmit uplink data without entering a connected state so that power consumption of the UE is reduced.