This　paper　gives　a　general　n-order　character　functional,　and　uses　the　quantitative　causal　principle　to　derive　the　general　variational　principle;　furthermore　the　Euler-Lagrange　equation　and　conservative　quantities　for　a　general　n-order　character　functional　are　derived,　and　the　link　between　the　principle　of　relativity　and　the　quantitative　causal　principle　is　revealed.　Newton＇s　first,　second,　and　third　laws　are　then　derived,　but　the　third　laws　is　also　regarded　as　a　new　law:　it　is　a　theorem　that　force　is　zero　in　translational　invariance,　and　its　general　physical　meaning　in　classic　mechanics　is　revealed.　The　results　obtained　have　been　successful　applied　to　the　galaxy　gravitational　potential　correction,　molecular　potential,　quark　confinement　potential,　etc.,　and　the　results　are　consistent　with　the　physical　experiments.