Aid and obstruction for TCSL teachers' professional development are mainly discussed by interviewing 10 teachers who have taught foreigners Chinese for some years. The findings in the paper are: 1. Keeping the concept of lifelong learning and encouraging teachers to pursue further education to enrich personal knowledge and abilities; 2. entering selves for an examination of teaching Chinese as a second to keep personal studying; 3. Interacting with other teachers to teach and learn promote and enhance each other; 4. Learning by doing, learning by experiences, which are helpful for teachers' professional development in teaching foreigners Chinese, but 1. inadequacy of internship courses; 2. inadequate hours of teacher education programs of teaching Chinese as a second language; 3. inadequate educators in teacher education programs of teaching Chinese as a second language; 4. resource limitations in the institutes of teacher education programs of teaching Chinese as a second language; 5. the myth of teaching experiences equaling professional knowledge; 6. being content with things as they are or being busy in teaching stop teachers from studying further, which impair teachers' motivation of continuing learning.