The invention relates to a method for measuring the trace amount chemicals in water mass and related analyzer, in particular an analyzing liquid and colorimetric analyzing tube for quick measurement of copper content in water mass. The copper analyzing liquid comprises 0.05% Phenanthroline compound 1-30 unit volume, and pH buffer liquid 1-20 unit volume, the analyzing tube contains uniform cross-section vacuum sealed glass tube, the glass tube is equipped with copper analyzing liquid, The ratio of the height H1 of the analyzing liquid in the glass tube and the height H2 of the glass tube uniform cross-section vacancy is H1 : H2 = 1:2-10. The invention can realize quick-speed simplified measurement, higher accuracy, and longer retention time.