公司之前身为香港长城(光学)塑料厂. 香港长城(光学)塑料厂在香港设厂成立至今已有四十多年，以生产塑料玩具相机而行销世界各地。自1975年起，转为生产简单实用之放大镜，80年代开始更进一步生产轻便型显微镜,90年代则涉足望远镜领域。时至今日，已有光学产品达六十多款。
香港长城(光学)塑料厂为配合长远发展计划，拓展中国新市场，于1995年将工厂整体迁移至中国东莞凤岗镇雁田管理区，成立东莞长城光学塑料厂有限公司(以下简称长城)，长城公司属(外商独资)企业，长城建筑总面积占地八千多平方米，厂房面积四千多平方米，并设有员工宿舍、饭堂、篮球、羽毛球场等。且预留土地作未来发展之用。
长城以生产塑料光学产品为主，其中包括各款放大镜、轻便显微镜及简便单筒、双筒望远镜等共六十多款，产品主要销往世界各地。除销售本厂现有产品外，亦接纳客户的特殊订单，来图或来样品由本厂负责设计或制造，配合现有产品或光学镜片，以满足客户需求。
长城为保持一向优良品质之厂誉，提高产品质量和产量，设计开发出更多类型之光学产品，务求拓展更大市场和销售量，长城已于1999年获得ISO9001质量体系证书，并以此为起点迈向卓越。
Over 40 years experience in the optical industry, the Greatwall (Optical) Plastic Works LTD., subsidiaries of the Hong Kong listed company, Cosmos Machinery Enterprises LTD. (HKSE: 0118.HK), has grown from a modest beginning to its present size and magnitude. Established in Hong Kong since 1960's, central offices and factories have been setup in Hong Kong in the early 60's, and Donguan, in the 90's.
Progressing steadily since inception, Greatwall has built up an unrivaled reputation in Optical Industrial and specializing in magnifiers and microscopes. Its popular brand " Waltex " and " Lumagny " have become well established in Hong Kong, China & US despite local and foreign competitions. With the very latest manufacturing facilities for top quality products, professional technical teams for research and developments and customer oriented marketing & sales teams for quality services, Greatwall continues to be one of the leading magnifiers and microscopes manufacturers in the region.
Innovation has been the key to Greatwall's success, with continual development of new products and manufacturing technology. Moreover, we are continually reviewing and upgrading logistics, marketing, distribution, product design practices. In these ways, we have become established as one of the most forward thinking companies in the industry.
产品系列
 New Product |
| Illuminated Magnifier |
| Magnifier |
| Microscope |
| Microscope with light |
| Binoculars |
| Waterproof Binoculars |
| Fresnel Lens |
| Quick List |
联系方式：
Hong Kong Head Office
Address: 7/F., Tai Tung Ind.Bldg., 29-33 Tsing Yi Road,
Tsing Yi Island, N. T., Hong Kong. (with effective from 18 DEC 2006)
Tel: (852) 2395 5265-8 (4 lines)
Fax: (852) 2789 0727
Email: greatwall@cosmel.com
greatwall@greatwalloptical.com.hk
Contacl person: Paul Cham
China Factory
Address: Beipu Ind. Zone, Zhentian Xi Lu, Yiantian Fenggang,
Dongguan City, Guangdong, China. Postal Code: 523702
Tel: 86-769-8777 0221-3 (3 lines)
Fax: 86-769-8777 3873
网址：http://www.greatwalloptical.com.hk
