Massive stars are rare, but play a key role in galaxy evolution. The formation of these stars remain poorly understood. We are performing a comprehensive survey of massive star formation in Cygnus-X, which is the most massive and active giant molecular cloud complex within 3 kpc from the Sun. Based on observations with the SMA, Jansky VLA, JCMT, IRAM-30m, Herschel, Spitzer, and Shanghai Tianma 65m radio telescope, we carry out a systemic study of the hierarchy of molecular cloud structures in the complex, aimed at constraining initial conditions of massive star formation and understanding to what extent high-mass protostars acquire mass in a way similar to their low-mass counterparts. I will introduce the progress of the survey and preliminary results from an analysis of a huge sample of molecular cloud cores. I may also talk about our new ALMA and NOEMA observations toward selected targets from the survey.
