The present disclosure provides a SONOS memory structure and a manufacturing method therefor. The SONOS memory structure including a substrate and a select transistor gate and a memory transistor gate formed on the substrate, wherein the substrate is a composite substrate including a base silicon layer, a buried oxide layer and a surface silicon layer, wherein the upper portion of the base silicon layer has a memory transistor well region formed therein; the select transistor gate and the memory transistor gate are formed on the surface silicon layer; the select transistor gate comprises a first select transistor gate and a second select transistor gate, the first select transistor gate and the second select transistor gate are respectively located at two sides of the memory transistor gate, and are electrically isolated from the memory transistor gate by first spacers on both sides of the memory transistor gate.