The invention discloses high-nitrogen austenitic stainless steel with intergranular corrosion resistance and pitting corrosion resistance superior to 316L after welding and a manufacturing method thereof. The high-nitrogen austenitic stainless steel comprises the following chemical components in percentage by mass: 0.03-0.06% of C, 0.25-0.80% of Si, 2.6-5.0% of Mn, 20.0-22.0% of Cr, 6.0-7.0% of Ni, 0.5-2.0% of Cu, less than or equal to 1.0% of Mo, less than or equal to 0.07% of V, less than or equal to 0.045% of P, less than or equal to 0.0020% of S, 0.2-0.3% of N and the balance of Fe and inevitable impurities. The C solid solubility concept is put forward for the first time, the C solid solubility of the material is improved, the C content is controlled to be smaller than the C solid solubility, Cr23C6 is prevented from being separated out in the welding process of the material, the intergranular corrosion resistance of the material after welding is improved, meanwhile, the pitting corrosion resistance equivalent PREN is controlled to be larger than or equal to 24.0, and the pitting corrosion resistance of the material is improved. Furthermore, an N solubility concept is provided, the N content is controlled to be smaller than the N solubility, the HCP phase precipitation temperature is controlled to be smaller than or equal to 1080 DEG C, the steel coil with good edge and surface quality is obtained, and the problem that corrosion resistance is reduced due to product surface defects is solved.