Intangible assets are long-term assets that are without physical attributes and not held for sale but are useful in the operations of a business.Such assets include patents，copyright，trademarks and goodwill.Their value to an enterprise is generally derived from the rights or privileges granted by governmental authority.

The basic principles of accounting for intangible assets are:(1)determining the initial cost;(2)recognizing the periodic cost expiration，called amortization.Amortization results from the passage of time or a decline in the usefulness of the intangible asset.In a broad sense，cash，receivables，financial assets，long-term equity investments，patents，trademarks，etc.，are regarded as intangible assets for they do not posses physical entities.However，in accounting，it usually takes a narrow sense，that is to say，refers patents，trademarks，etc.as intangible assets.