The new Hong Kong senior secondary science curriculum will be implemented in 2009. The curriculum change was induced by the change in the education system, but its meaning will go far beyond matching the curriculum with the new system. It intends to remove the limitation of the existing curriculum, and to enlighten it with essential elements of contemporary science education. It transcends subject boundary to establish a new integrated subject, and extends the scope of student assessment such that both teaching and assessment will become more diversified. This article analyses the characteristics of this curriculum reform and its forces behind, and comments on the advantages and challenges it create.