The mesh belt type steel tube annealing furnace adopts the non oxidation continuous heat treatment furnace with protective gas to carry out the heat treatment in the production process, the intermediate heat treatment and the final product heat treatment, because the non oxidation surface can be obtained. Therefore, the traditional pickling process is canceled. The adoption of this heat treatment process not only improves the quality of steel pipe, but also overcomes the environmental pollution caused by pickling. The workpieces that need heat treatment are put on the continuous running mesh belt. When heated in muffle tank, all kinds of alloy pipes and bars can be treated with low cost. The output per hour is more than 0.3 tons, and the protective gas is usually nitrogen with purity of 99.99%. As the workpiece is annealed in protective atmosphere, the product is soft, bright, no oxidation and zero decarburization.