Using the 13.7 m radio telescope at Qinhai Station of Purple Mountain Obser
vatory, new observational results have been obtained for 5 planetary nebula
e. Among them, the CO(2-1) emission of M1-8 and M3-3 has been detected and
the results of observation of their CO(1-0) emission are presented in this
paper. For the other objects, i.e., M1-12, M2-43 and NGC 6537, for which pr
evious CO observations failed to detect CO emission, their CO(1-0) emission
is here identified for the first time.