Protons are the basic particles that make up the universe. Since Ernest Rutherford discovered protons in 1919, great progress has been made in the study of protons in particle physics. Protons are composed of quarks and gluons, and quarks are divided into valence quarks and sea quarks. At present, particle physics has not paid attention to the study of the mass relationship between three valence quarks in protons. Because quarks are confined in protons, the mass of quarks cannot be obtained directly from experiments, so there is a lack of experimental basis for research. So ,Is there any way to find the relationship between the three valence quarks in protons? In this paper, a new research method is found. By finding the exact ratio of the mass of the up quark and the down quark, the relationship among the three valence quarks can be found. At the same time, the discussion on Higgs mechanism and vacuum condensation of QCD can be avoided. Based on the experimental results of seaquest carried out by Fermilab in 2021, through analysis, the accurate ratio of up quark to down quark mass (mu/md=0.707) is obtained, and the mass triangle is established. It is deduced that the sum of squares of up quark mass in protons is equal to the square of down quark mass. The mathematical expression is: mu²+ mu²= md²; According to the observation of the decay law of other baryons, the quark law in baryons is obtained: except protons, the heavy quarks in other baryons will decay into up quarks or down quarks, and the sum of squares of up quarks should be equal to the square of down quarks.According to mu²+ mu²= md², it is deduced that there are three generations of protons in the universe, in order to remind people to rethink the protons in the universe. The core of the view that there are three generations of protons in the universe is that the proton in the center of the star and the proton valence quark on the surface are different. Using the viewpoint that there are three generations of protons in the universe, we can explain some unsolved mysteries of the sun, analyze the reasons for the expansion of the universe, and create conditions for the final cracking of dark matter and dark energy.