The present invention provides a 1.5T SONOS memory structure and a manufacturing method, comprises a P-well and a storage well on its side, gates of a select transistor and a storage transistor; the height of the select transistor gate is less than the height of the storage transistor gate, an stack layer is between the gats of the select transistor and the storage transistor which height is same as the storage transistor gate; the top of the select transistor gate has a first sidewall; the sidewall of the select transistor gate has a second sidewall. The present invention strengthens the isolation between the gates of the select transistor and the storage transistor, reduces the risk of current leakage, enables the metal silicide to also grow on the gate of the select transistor, reduces the resistance of the select transistor and improves the performance of the device.