The invention provides a heavy oil processing method and system. The heavy oil processing method comprises the following steps: step A: enabling hydrogen-enriching gas and a heavy oil raw material toreact in a low-temperature plasma reactor, so as to generate a first product, wherein the weight ratio of the hydrogen-enriching gas to the heavy oil raw material is (0.001 to 0.2) to 1, preferably (0.005 to 0.15) to 1; step B: carrying out delayed ageing on the first product to generate a second product; step C: carrying out fractional distillation on a gas-liquid component in the second productso as to obtain products of different fractions. Based on unique activity of plasmas, a traditional delayed coking reaction process is strengthened to activate raw oil, so that the yield of liquid oilis improved; meanwhile, water steam does not need to be injected into a coking heating furnace, the discharging amount of technological wastewater is remarkably reduced and the heavy oil processing method and system are more environmentally friendly.