Aims: Magnetic fields exist on all scales in our Galaxy. There is a controversy on whether the magnetic fields in molecular clouds are preserved from the permeated magnetic fields in the interstellar medium (ISM). We want to check this controversy using available data in the light of the newly revealed magnetic field structure of the Galactic disk obtained from pulsar rotation measures (RMs). Methods: We collected the measurements of the magnetic fields in molecular clouds, including Zeeman splitting data of OH masers in clouds and OH or HI absorption or emission lines of clouds themselves. Results: These Zeeman data show structures in the sign distribution of line-of-sight component of magnetic field. Comparing with the large- scale Galactic magnetic fields from pulsar RMs we found that the sign-distribution show similar large-scale field reversals. Previous such examinations were flawed by the over-simplified global model for the large-scale magnetic fields in the Galactic disk. Conclusions: We conclude that the magnetic fields in the clouds may still "remember" the directions of magnetic fields in the Galactic ISM to some extent, and could be used as completementary tracer for the large-scale magnetic structure. More Zeeman data of OH masers in widerly distributed clouds are desired for such a study.