The mean global surface air temperature data indicate that there might be a global warming hiatus during 1998-2012. However, whether it existed around the world is still controversial, and the characteristics of the hiatus in Northwest China remain unclear. Based on the in-situ observation data of air temperature from 1960 to 2019, we analyzed the characteristic of hiatus in Northwest China through the cumulative anomaly curve, the Mann-Kendall test, Move-t test, the Yamamoto test and the linear trend estimation. The results showed that the statistically significant change-point of the annual mean air temperature in Northwest China was in 1986, 1996, and 2012, respectively. The air temperature suddenly rose in 1996, and then kept stable from 1998 to 2012. The annual mean air temperature showed an obvious cooling trend by -0.20 ℃ decade^-1 in Northwest China from 1998 to 2012. Meanwhile, the annual mean air temperature in winter had the largest decrease rate and that of summer increased. The east of Northwest China displayed the most significant cooling during 1998-2012, and the Tibetan Plateau was still heating up at the same time. The air temperature of Northwest China rose substantially after 2012, especially in winter, and southern Xinjiang experienced the strongest warming during 2012-2019. Generally speaking, the warming hiatus was evident in Northwest China during 1998-2012 except the Tibetan Plateau. Therefore, more attention should be paid to the marked upward trend in air temperature after the hiatus in Northwest China due to the crucial environment.