Abstract: The Tekken test using E10018 electrode and finite element (FE) simulation to evaluate the cold cracking susceptibility of X100 pipeline steel has been performed. The impact of preheating condition on the HAZ microstructures, distribution of hardness, and the stress-strain state in the welded joint was analyzed. The experimental results showed that X100 pipeline steel reveals certain susceptibility to cold cracking without preheating. It was found that preheating temperature below 100℃ resulted in a lower cold cracking susceptibility. Preheating temperature of 100℃ is most effective with zero cracking ratios due to a relative fine CGHAZ microstructure and low M-A constituent amount, a low hardenability, low level stress and strain level. However, excessive preheating temperature of 150℃ and 200℃ can lead to higher cold cracking susceptibility due to an increase in CGHAZ grain size, M-A constituent amount, equivalent stress level and strain level in the Tekken specimens. Preheating temperature of 100℃ is recommended to reduce cold cracking.