This　paper　considers　robust　estimation　of　varying　coefficient　model　with　emphasis　on　resistance　against　outliers.　By　combining　B-splines　method　with　taut　string　method,　a　penalized　B-splines　procedure　is　proposed.　Based　on　local　quadratic　approximation,　an　iterative　algorithm　is　introduced.　A　simulation　study　is　undertaken　to　assess　the　finite　sample　performance　of　the　proposed　method.　An　example　in　epidemiology　is　used　for　illustration.