The work aims to preferably select carboxylated multi-walled carbon nanotubes (c-MWCNTs) and graphene oxide (GO) as sensitive materials to prepare humidity sensor and study the humidity sensitivity characteristics of the sensor to explore a novel sensor that can quickly and accurately monitor the humidity changes in the packaging. The sensor electrode substrate was printed by screen printing process, and the c-MWCNTs/GO humidity sensitive solution was coated on the electrode surface. The mass fraction of c-MWCNTs in the mixed humidity sensitive solution was 20% and 67%, respectively. After drying, a resistive humidity sensor was prepared. The sensitivity, dynamic response, response recovery time, hygroscopic lag and other hygroscopic sensitive characteristics were measured. The humidity sensor prepared with c-MWCNTs of length 0.5~2 μm had better sensitivity and linearity than those prepared by c-MWCNTs of 10~30 μm. The sensor prepared with 20% and 67% mass fraction of c-MWCNTs in the humidity sensitive solution was sensitive to different humidity levels, and the sensitivity and linearity were higher when the mass fraction of c-MWCNTs was 67%. The response and recovery times were 7 s and 3.9 s, respectively at low humidity (33%RH) and 20 s and 15 s, respectively at high humidity (85%RH). The maximum hygroscopic lag value was 17%. The c-MWCNTs can be doped with GO to prepare humidity sensor, which can detect the changes of relative humidity from 11% to 98%, and the sensor prepared by 67% mass fraction of c-MWCNTs has high sensitivity, good linearity, excellent repeatability, fast response recovery and small hygroscopic hysteresis, thus having a broad prospect in the future application of packaging humidity monitoring.