A child bicycle seat releasably mounted to a bicycle includes a seat assembly including a child seat secured to a tube member, a front tube mounted to a front end of the tube member and having top and bottom cavities, and a quick release clamp mounted to a rear end of the tube member; a handlebar assembly including a hollow pole having two opposite lower slots, a handlebar member threadedly secured to a top of the hollow pole, and a first quick release skewer secured to both the top cavity and the lower slots to fasten the front tube and the hollow pole together; a clamp assembly including a top tube having two opposite slot members, a second quick release skewer secured to both the bottom cavity and the slot members to fasten the front tube and the top tube together. The clamp assembly has a height adjustment mechanism.