The construction of a thin stable shell to encapsulate perovskite with effective carrier transport is a promising strategy to fabricate highly efficient and stable perovskite based optoelectronic devices. However, it is generally difficult to control the thickness and location of the encapsulating materials, ideally on perovskite grains. In this work, we developed a one-step method for the growth of titanium alkoxide networks in-situ in perovskite film forming an encapsulating layer on perovskite nanograin homogeneously. The thin encapsulating network brings much enhanced stability and allows effective carrier transport simultaneously. Light emitting diode based on this composite shows much enhanced stability under continuous operation.