JVT Scalable Video Coding (SVC) provides high coding efficiency for progressive video sequences with combined scalability. However, interlaced SVC is only the straightforward extension of H.264/AVC interlaced coding with the similar FGS coding technique for progressive coding. Based on the particular temporal correlation of interlaced video sequences, this paper presents a novel and efficient FGS coding scheme for interlaced SVC, which is able to achieve higher compression efficiency and further temporal scalability by introducing additional temporal decomposition stage when coding key pictures. The advantages of our proposed interlaced FGS coding scheme are verified by integrating it into JVT-SVC reference software.