本文利用三階段賽局的設計，討論工會成立與民營化政策的相關議題，本文獲得以下幾項分析結果，1.在公營廠商沒有工會、工資與民營廠商掛勾下，當公民營廠商生產力差距較小時，民營化程度應降低；當公民營廠商生產力差距較大時，民營化程度應提高。一旦公營廠商成立工會協商工資後，保持完全公營為社會福利最大考量。2.政府在極大社會福利考量下，應禁止公營事業成立工會協商工資。3.公營事業工會設立與民營化政策具有互斥性。

This paper uses a three-stage game to discuss the establishment of labor union and privatization policy of the public firm. This paper finds that: 1. When public firm has no labor union, and wages are linked to private firm, if the productivity gap between public and private firms is small, the degree of privatization should be reduced; the degree of privatization should increase when the productivity gap is large. Once the public firm sets up labor union to negotiate wages, a completely public firm will enhance the social welfare. 2. In the view of social welfare, the government should prohibit public firm to establish a union to negotiate wages. 3. The establishment of public labor union and privatization policy are mutually exclusive.