The E1A signal of Galileo system provides high-precision location information service for authorized users. The confidentiality of codes and the auto-correlation multi-peaks of high-order Binary Offset Carrier lead to the lack of relevant research on the quality assessment of E1A signal in the real environment. In this paper, two kinds of high-order BOC tracking algorithms including Bump-Jump and Double Estimator (DET) Technical are studied ,then their principles how to eliminate the correlation curve multi-peaks are introduced and compared about advantages and disadvantages. Based on DET, the E1A tracking loop is initialized by using the E1B signal's carrier information, and then the spreading code modulated message symbol is accurately recovered by waveform-matching method, so the tracking problem of the E1A actual signal is solved. Based on the tracking information of E1A signal, we perform the evaluation of S-Curve Bias (SCB) and correlation loss, and compared those with E1B signal. The results show that the E1A signal correlation loss is greater than the E1B signal, and within 0.15 chip correlator spacing, both SCB are within 0.1ns. The results have verified the effectiveness of the assessment method of E1A signal quality, as an important reference for improving signal analysis and assessment of GNSS.