This article explores the complexity of risk and the trend of technicality in risk governance. Through the interlocution between rational determinism and social constructionism, we argue risk, as knowledge of society, implies the will to predict, control as well as the attempt at interpretative flexibility, discretion and responsibility-taking. Risk is not simply an object ＂out-there＂. Risk is situated at the crossover between expert knowledge and lay knowledge in modern society, which includes the creation and (re)arrangement of institutions with production of sets of knowledges. Expert knowledge consists of social commitments and assumptions. It rearranges practices, conventions and social relationship to acquire its validity and legitimacy. Lay knowledge surely doesn't just distrust experts. It is situated in life world and comprises of local experience, practices and conventions with the potential of theory and practicality. Its capacity of political mobilization is unneglectable. With the review on the matrix of uncertainties proposed by Renn and Stirling. This article doesn't intent to deny the value of expertise of risk governance; nonetheless, it insists risk governance should not be reduced to the institutionalized expertise of risk management and scientific risk assessment. Therefore, going beyond the demarcation line of expert and lay knowledge is needed, which aims for the imagination of collective experiment, human agency and creativity of risk society.