Based on the Doppler weather radar data in Jinan, sounding data, and weather observations, the intensity structures, flow field structures, and environmental parameters of two isolated long-lived non-supercell storms with duration more than 4 hours are comparatively analyzed. The results show that Storm 0611 and Storm 0915 both occurred under interactions between northwest airflow and lower-layer shear line at the bottom of cold vortex over Northeast China. At the same time, the environmental situation is dry and cold in the upper layer, while warm and moist in the lower layer. Strong vertical wind shear appears between 0 and 6 km and DCAPE (downdraft convective available potential energy) from 600 hPa is relatively high. In the vigorous stage, the mean values of DBZM (maximum reflectivity), C-VIL (cell-based vertically integrated liquid water), and HT (centroid height) of Storm 0915 are significantly higher than those of Storm 0611, and the difference values are 6.7 dBZ, 11 kg·m-2, and 2.4 km, respectively. For mature Storm 0915, the middle-layer airflow structure is characterized by MARC (mid-altitude radial convergence) in the early stage, strong cyclonic rotation in the intermediate stage, and MARC with stronger convergence in the later stage. For vigorous Storm 0611, the middle-layer airflow structure is characterized by double-vortex flow pattern, cyclonic rotation intensity significantly higher than anticyclonic rotation intensity in the early stage, and anticyclonic rotation intensity significantly higher than cyclonic rotation intensity in the later stage. For the two processes, the environmental parameters of CAPE and lower-layer specific humidity differ greatly, and the lower-layer specific humidity of Storm 0915 is significantly higher than that of Storm 0611. Under similar situations, high lower-layer humidity, high CAPE value, and high speed of updraft inside the storm are conducive to the overhang and maintenance of the strong reflectivity core.