We present the most recent studies of diboson production and electroweak physics in proton-proton collisions at 7TeV and 8TeV center-of-mass energy based on data recorded by the CMS detector at the LHC in 2011 and 2012. These include precise measurements of γγ, ZZ and WZ production. Results on triboson production of WWγ and WZγ are also presented. The results are interpreted in terms of constraints on anomalous triple or quartic gauge couplings. We also review
some recent electroweak physics results, including the purely electroweak Z bosons production cross section and the muon charge asymmetry measurement. The results are compared with Standard Model prediction
