A numerical simulation on thermodynamical mechanism of a heavy precipitation supercell development in Beijing-Tianjin-Hebei area is implemented by using a three-dimensional cloud-scale numerical model and rapid update cycling 4-D variational assimilation (4DVar) technique of radar data. The analysis on the simulation results and observations of radars, rawinsondes, and Automatic Weather Stations (AWSs) denotes the effects of frequent variational 3-D thermodynamical attribute of storm and storm-relative environment on initiation, intensification, and development of the supercell. The analysis on radar observations indicates the supercell storm with right-moving property evolves from multi-cell storms merging and splits into multi-cell storms again. The simulation results show low-and middle-layer vertical wind shears gradually intensify in the front of the storm that is favorable to form quasi-steady, strongly rotating updraft and mesocyclone in the supercell storm during the period of the supercell initiation and enhancement. The hodographs analyzed by simulated winds indicate the low-level vertical wind shear has significant clockwise-curved attribute in front of storm that is favorable to strengthening and right-moving of the supercell. The simulation also reveals that the cold pool, convergence of outflow (gust front) and low-level wind, and updraft ahead of the supercell continually strengthen along with the storm development, which results in warm and moist low-layer air ascending ahead of the storm continuously. The ascending air revolves into storm under the impact of strong vertical wind shear that maintains and strengthens the supercell storm. During the period of the supercell dissipation and split, the simulation results indicate that all of thermodynamical structures are unfavorable to further development of the supercell. The vertical wind shear weakens evidently and contributes a unidirectional (straight) hodograph that is only conformable to multicell storms. The perturbation temperature shows that the cold pool further intensifies and expands with greater speed than the storm motion during the period. The low-layer winds indicate the outflow boundary (gust front) becomes much intense and forward, and is away from the storm. The low-level convergence and updraft are also weaker during the period than those during the period of the supercell enhancement. The storm-relative environment helicity (SREH), storm bulk Richardson number (SBRN), and storm strength (SS) are calculated by using the simulated data. The results indicate SREH＜150 m²/s², SBRN＜45, and SS＞0.4 during the period of the supercell initiation and enhancement, and the reversed conclusion during the period of the supercell dissipation and split. The coincident conclusion with other investigations implies the simulated SREH, SBRN, and SS are significant to indicate development of the storm case.