Seaweed biotechnology is a multidisciplinary subject to produce food, pharmaceuticals, chemicals, and environmental remediation materials from seaweed resources. It uses various techniques of cell culture, enzyme reaction and genetic manipulation to increase the production efficiency of useful seaweeds or their products. Firstly, an overview of key topics will be introduced in the fields of seaweed tissue culture, strain improvement, genetic analysis briefly as basic techniques. Secondly, some biologically active substances such as anti-inflammatory and antifouling substances that have been screened in my laboratory will be focused.