A microwave-assisted flash pyrolysis system, comprising: at least one microwave generator connected to a chamber; wherein the chamber comprises: at least one feedstock inlet, at least one first baffle plate, a microwave-transparent rotating window, and at least one microwave inlet, at least one wet gas outlet, and at least one dry-end product outlet; wherein the feedstock inlet for introducing feedstocks to the microwave-transparent rotating window is disposed over the microwave-transparent rotating window and in front of the first baffle plate; wherein the first baffle plate is used for leveling out the feedstocks on the microwave-transparent rotating window and separating the chamber into different pyrolysis sectors in which flash pyrolysis is to take place; wherein the first baffle plate is disposed over the microwave-transparent rotating window, and there is a gap between the first baffle plate and microwave-transparent rotating window; wherein the height of the gap is adjustable and used for determining the thickness of input feedstocks; wherein the microwave-transparent rotating window moves the input feedstocks through the gap and into the pyrolysis sector; wherein the pyrolysis sector is disposed over the microwave inlet; wherein the microwave inlet is connected to the microwave generator for introducing microwave energy upward into the pyrolysis sector that is disposed over the microwave-transparent rotating window and limiting the microwave energy between the first baffle plate and the dry-end product outlet; wherein the wet gas outlet is connected to a gas collection unit for collecting wet gas from the pyrolysis sector, and the wet gas outlet is disposed over the microwave-transparent rotating window; wherein the dry-end product outlet is connected to the chamber for collecting pyrolyzed dry-end products from the microwave-transparent rotating window. at least one microwave generator connected to a chamber; wherein the chamber comprises: at least one feedstock inlet, at least one first baffle plate, a microwave-transparent rotating window, and at least one microwave inlet, at least one wet gas outlet, and at least one dry-end product outlet; wherein the feedstock inlet for introducing feedstocks to the microwave-transparent rotating window is disposed over the microwave-transparent rotating window and in front of the first baffle plate; wherein the first baffle plate is used for leveling out the feedstocks on the microwave-transparent rotating window and separating the chamber into different pyrolysis sectors in which flash pyrolysis is to take place; wherein the first baffle plate is disposed over the microwave-transparent rotating window, and there is a gap between the first baffle plate and microwave-transparent rotating window; wherein the height of the gap is adjustable and used for determining the thickness of input feedstocks; wherein the microwave-transparent rotating window moves the input feedstocks through the gap and into the pyrolysis sector; wherein the pyrolysis sector is disposed over the microwave inlet; wherein the microwave inlet is connected to the microwave generator for introducing microwave energy upward into the pyrolysis sector that is disposed over the microwave-transparent rotating window and limiting the microwave energy between the first baffle plate and the dry-end product outlet; wherein the wet gas outlet is connected to a gas collection unit for collecting wet gas from the pyrolysis sector, and the wet gas outlet is disposed over the microwave-transparent rotating window; wherein the dry-end product outlet is connected to the chamber for collecting pyrolyzed dry-end products from the microwave-transparent rotating window.