Abstract: Combined with the stochastic lightning parameterization scheme of self-initiated upward lightning, a fixed background electric field is set, and then 2-dimensional fine-resolution lightning discharge simulations are performed to investigate the effect of building height on single upward lightning trigger and propagation. The results show: (1) The upward lightning branch is less in the initial stage; to about 2 km away from the ground, the upward lightning begins to appear a lot of branch, the lightning channel begins to appear obvious bifurcation: some part of the path transmits to the high charge density centre vertically, and another part of the channel bypasses the high charge density with outward horizontal transmission; the upward lightning vertical transmission reaches only to 4 km, where is the negative charge center located, and it is unable to reach, through the zero potential line, to the positive charge area above. (2) Building height plays a key role in upward lightning trigger, and it is more likely to trigger the upward lightning with the increasing height. And (3) building height has certain adverse effect on upward lightning spread, and with the increase of building height, the horizontal and vertical propagation distance of upward lightning, the fractal dimension and the total propagation length of the lightning channel are all decreased gradually.