Fault diagnostic analysis is an important evaluation in the design and maintenance of multiprocessor systems. The g-good-neighbour conditional diagnosability is the maximum number of faulty vertices a multiprocessor system can guarantee to identify under the condition that every fault-free vertex has at least g fault-free neighbours. In this paper, we first establish the -connectivity of multiprocessor system based on half hypercube and then show that the g-good-neighbour conditional diagnosabilities of half hypercube under the PMC model and MM* model are for and . As a by-product, we also derive the g-good-neighbour conditional diagnosability of hierarchical cubic network since an n-dimensional half hypercube network is isomorphic to an n/2-dimensional hierarchical cubic network when n is even.