Symbolic representation refers to the use of physical or psychological processes to represent an object in a symbolic form. The present study investigated the development of children's symbolic representation using a new measure of children's block constructions. Ninety children (44 girls) in three age groups (3-4, 4-5, and 5-6 years) were randomly assigned to reproduce an example of ancient Chinese architecture using either two-dimensional pictures or a three-dimensional scale model. Children in the 3-4 age group produced significantly better constructions in the pictures condition. This picture-superiority effect disappeared in the 4-5 age group. In the 5-6 age group, there was better dimensionality in children's constructions when they used a scale model as the referent. The data identified the age of 4-5 as a critical period for the development of children's symbolic representation to transfer relational information from a scale model to their construction.