The objective value of any commodity, service or asset can only be revealed by its trading price conditionally. That means, the government must first establish its money as the domestic stable objective value scale via its public right. In this paper, the author differentiates two kinds of beforehand thinking about trading price. One is with strong subjectivity, the other is with strong objectivity. He demonstrates that the trading prices generated from the circular flow of economic activity, the non-land asset circulation, or the quasi-money asset circulation often possess the stability, while the trading prices generated from the land asset circulation or the non-quasi-money asset circulation possess the instability frequently.