The invention belongs to the technical field of semiconductors, and in particular relates to a nonvolatile memory unit, a memory and an operating method. The nonvolatile memory unit consists of three transistors, namely a control transistor Mc, a tunneling transistor Mt and a selecting transistor Ms, wherein the grid electrode of the control transistor Mc and the grid electrode of the tunneling transistor Mt are connected to form a floating gate; the drain electrode of the tunneling transistor Mt is connected with the drain electrode of the selecting transistor Ms; the source electrode of the tunneling transistor Mt is connected with a substrate; the substrate of the selecting transistor Ms is grounded. The nonvolatile memory consists of a plurality of the nonvolatile memory units which are connected in parallel. Compared with the existing common storage structures, the nonvolatile memory unit and the memory, which are provided by the invention, have the advantages that the unit area is small; the number of interfaces is small; the memory capacity is increased to a certain degree, and the complexity of a memory array peripheral circuit is reduced. The operating method provided by the invention is simple to operate and facilitates implementation of related functions of the memory.