Pitting corrosion resistance and mechanical properties of 2304 duplex stainless steel with different Crcq/Nicq values after plasma-arc welding and welding thermal simulation were systematically studied.The results showed that the lower the Creq/Nieq value in the experimental range,the better the microstructure after welding or welding thermal cycle.High pitting resistance equivalent number in the chemical composition brought in low weight loss rate and high critical pitting temperature for base metal.Furthermore,the degradation of pitting corrosion resistance after welding thermal cycle was less.while the Creq/Nieq value was lower.