In the event-related potential (ERP) studies of visual attention, there is a debate regarding whether the C1 component, originated in V1, is modulated by spatial attention. The majority view suggests that C1 is not directly modulated by spatial attention; however, there is a delayed-feedback in V1. The minority view, on the other hand, implies that the C1 component can be directly modulated by spatial attention at the early feed-forward processing stage. Recently there was a debate regarding this issue. In this review, we first summarize the main points and evidence for each side. Second, we listed the factors that may affect the C1 attentional effects. Third, we review and comments on the recent discussions on three aspects, including the repeatability of C1 attentional effect, the role of perceptual and attentional load in eliciting this effect, and the relationship between C1 polarity reversal and its V1-origin. Finally we proposed two points of view: the first is that we should be open and cautious towards the minority view, and the second, there are some techniques and methods that may help to reveal the potential C1 attentional effect. In conclusion, the majority view has been supported by many previous studies and the minority view needs more decisive evidence, and this debate will continue.