The measurement of δ ferrite contention in the weld of austenitic stainless steel is a key step of the welding procedure qualification and the acceptance of welding materials and welding certificate. There are controversial and confused points in RCC-M standard about the measurement of δ ferrite contention in the weld of austenitic stainless steel. Put forward some cognition and understanding about the controversial and confused points in RCC-M standard and discuss a series of problems of the measurement of δferrite contention in the weld of austenitic stainless steel combined with the practical engineering experience and formation mechanism of ferrite in weld. The relevant controversial items concerning the determination of δ ferrite content in austenitic stainless steel welds in S section of RCC-M are clarified.