Abstract: The invention describes and claims a processing plant and a method for processing viscous oil and oil products. The processing is effectuated with a plant, which comprises a plurality of reaction modules, a plurality of rectifying chambers and pipelines. Each reaction module and each rectifying chamber comprises a tank, a pump, a hydrocavitation generator. Each reaction module comprises a plurality of intermediate reaction stages. Each rectifying chamber comprises a plurality of intermediate rectifying stages. The reaction module and the rectifying chamber are interconnected. Intermediate reaction stages are connected by pipelines, with the last one connected to a rectifying chamber.