This invention relates to a LED illuminator and its manufacturing method. The lamp is composed of a transparent lampshade, a drain pan, a LED group, a CB and a controller. Numbers of single small power LED, shape and light output are determined according to the needs of intensity of illumination, each LED forms at least a parallel and a serial branch in the connection way of parallel in two-two or parallel in multiple then in series, which are parallel again to compose a parallel-serial-parallel mixed LED circuit to constitute a LED group. The shape of the CB is a regular phone or curve or not, a constant current control circuit is set in the controller, its output is connected with the load LED group and a double-mode pulse control circuit via an output current feedback circuit and a regulated supply circuit, the pulse control circuit controls the LED group by the switch circuit.